1. Field of the Disclosure
The present disclosure relates to an image recording apparatus that records an image on a recording medium by discharging droplets from a recording head.
2. Description of the Related Art
A conventional image recoding apparatus discloses an inkjet recording apparatus including line-type recording heads each having an ink discharging surface with nozzles for discharging ink, and a conveyor belt laid between two rollers (hereinafter referred to as a line-type recording apparatus). In this recording apparatus, a recording sheet is conveyed while being drawn onto a conveying surface of the conveyor belt facing the ink discharging surface, and an image is recorded on the recording sheet by selectively discharging ink from the recording heads onto the recording sheet. Herein, a line-type recording head has a length corresponding to the width of a recording sheet in a direction orthogonal to the conveying direction of the recording sheet, and can record an image on a surface of the recording sheet conveyed by a conveying means, such as a conveyor belt, while staying at rest. An inkjet recording apparatus is also known which includes a so-called serial scan recording head that reciprocates in the direction orthogonal to the conveying direction of a recording sheet (hereinafter referred to as a serial-type recording apparatus). This serial-type recording apparatus records an image on the recording sheet by alternately repeating the conveyance of the recording sheet and the forward or backward movement of the recording head. Since the line-type recording head itself does not move during recording, as described above, it can perform image recording at a speed higher than that of the serial-type recording apparatus.
In the line-type recording apparatus disclosed in the above publication, a recording sheet on the conveying surface sometimes lifts from the conveyor belt, for example, when the recording sheet is curled. Particularly when the recording sheet is relatively thick and sturdy, it easily lifts from the conveyor belt. Depending on the degree of this lifting, the recording sheet sometimes rubs against the ink discharging surface. Consequently, the recording sheet is soiled with unnecessary ink, and this may lead to waste of recording sheets and damage to the ink discharging surface of the recording head. Moreover, the recording sheet sometimes jams, and this brings about frequent maintenance operations by the user.
Accordingly, in the line-type recording apparatus disclosed in the above publication, a detection mechanism for detecting lifting of the recording sheet from the conveyor belt is provided upstream from the recording heads in the conveying direction of the recording sheet. When lifting of the recording sheet is detected by the detection mechanism, the recording apparatus executes control to stop the conveyance of the recording sheet in order to avoid the above-described problems due to the contact of the recording sheet with the ink discharging surface.
However, when recording is stopped by stopping the conveyance of the recording sheet every time lifting of the recording sheet is detected, as described above, the operating efficiency of the line-type recording apparatus decreases. In particular, if the recording operation is frequently interrupted, the line-type recording apparatus loses the advantage in its capability to perform image recording at a speed higher than that of the serial-type recording apparatus.